As per the kinetic theory of gases,which of the following statements is/are true?
$(a)$ Temperature of a gas is a measure of the average kinetic energy of a molecule.
$(b)$ Temperature of a gas depends on the nature of the gas.
$(c)$ Heavier molecules have lower average speed.
$(d)$ Lighter molecules have lower average speed.

If the collision frequency of hydrogen molecules in a closed chamber at $27^{\circ} C$ is $Z$,then the collision frequency of the same system at $127^{\circ} C$ is :

$N$ molecules each of mass $m$ of gas $A$ and $2N$ molecules each of mass $2m$ of gas $B$ are contained in the same vessel at temperature $T$. The mean square of the velocity of molecules of gas $B$ is $v^2$ and the mean square of $x$ component of the velocity of molecules of gas $A$ is $w^2$. The ratio $\frac{w^2}{v^2}$ is

Saturated vapour is compressed to half its volume without any change in temperature,then the pressure will be

$A$ container holds $10^{26} \text{ molecules/m}^3$ each of mass $3 \times 10^{-27} \text{ kg}$. Assume that $1/6$ of the molecules move with velocity $2000 \text{ m/s}$ directly towards one wall of the container while the remaining $5/6$ of the molecules move either away from the wall or in perpendicular direction,and all collisions of the molecules with the wall are elastic.

$(a)$ When a molecule (or an elastic ball) hits a massive wall,it rebounds with the same speed. When a ball hits a massive bat held firmly,the same thing happens. However,when the bat is moving towards the ball,the ball rebounds with a different speed. Does the ball move faster or slower?
$(b)$ When gas in a cylinder is compressed by pushing in a piston,its temperature rises. Guess at an explanation of this in terms of kinetic theory using $(a)$ above.
$(c)$ What happens when a compressed gas pushes a piston out and expands? What would you observe?
$(d)$ Sachin Tendulkar used a heavy cricket bat while playing. Did it help him in any way?